1995 Mazda 626 Engine bucks at 2000 RPM

RAYSMITH333

MEMBER
1995 MAZDA 626

Engine Performance problem
1995 Mazda 626 4 cyl Front Wheel Drive Manual 124K miles

My car bucks (not missing) when accelerating at 2000 rpm not matter what gear I am in.

Two car pros suspected a bad EGR valve. I disconnected the vacuum line from the EGR valve and test drove the car. The problem persisted. I checked the EGR valve per 2 car pro instruciton, RPM dropped as it should have when applying 6-10 inches of vacuum.

What is the next thing to check?

2 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

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Monday, May 25th, 2009 AT 6:10 AM

KHLOW2008

MECHANIC
41,815 POSTS

Hi Raysmith333,

Please reply to this post by clicking the reply to question link so that notification to technicians are received. Editing the contents will not be notified so we would not be able to keep track.

Replying to same post would keep the history of info exchanged togther for easier reference.

As my fellow technician has replied to you regarding the possibilities, if you require any testing procedures, we would be happy to provide them.

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